Disposable diaper

ABSTRACT

A disposable diaper comprising a fluid-permeable topsheet, a fluid-impermeable backsheet and a fluid-retentive absorbent core interposed between the topsheet and the backsheet, the disposable diaper being formed in a substantially vertically elongated configuration and having a stomach side, a back side and a crotch region positioned between the stomach side and the back side, wherein a second absorbent core is disposed at an outside region of each opposite side edge of the absorbent core at the crotch region along a longitudinal direction of the diaper, and an elastic member is disposed at the region where the second absorbent core is disposed along a longitudinal direction of the diaper.

This application claims the priority of Japanese Patent Application Nos.2000-402839 filed Dec. 28, 2000, 2001-11155 filed Jan. 19, 2001,2001-66189 filed Mar. 9, 2001 and 2001-178184 filed Jun. 13, 2001, whichare incorporated herein by reference.

BACKGROUND OF THE INVENTION

This invention relates to a disposable diaper excellent inleak-preventive property and capable of preventing leak occurrableparticularly around the leg areas. This invention also relates to adisposable diaper excellent in storability/retainability of an auxiliaryabsorber, wearability (property of feel in wear and easy application toa wearer) and/or fitness at the crotch region and the like, in additionto its excellent leak-preventive property.

Heretofore, it has been an important problem for disposable diapers howto prevent leak occurrable around the leg areas. Japanese PatentPublication No. 05-33630 discloses a disposable diaper in which anabsorbent core is comprised of a central absorbent section of a width inconformity with the human body and an outer absorbent section disposedoutside thereof, so that close fit to a wearer at the crotch region isenhanced, thereby improving the leak-preventive property. However, thisdisposable diaper has such a problem that wrinkles are liable to occurto the central absorbent section due to contraction of an expansiblepart placed between the central absorbent section and the outsideabsorbent section, and therefore urine and excretions can easily leakfrom the central absorbent section along the wrinkles. Moreover, sinceit is designed such that leak is prevented by enhancing the fit at thecentral absorbent section, those urine and excretions leaked out towardsthe opposite sides from the central absorbent section can reach theoutside absorbent section comparatively easily, and especially, in casethe amount of excretions is large, those feces and urine easily leakoutside beyond the outside absorbent section.

Moreover, since the outside absorbent section is difficult to deformalong the contour of the wearer's body, wearability and fitting propertyat the crotch region are deteriorated.

Japanese Patent No. 2712044 discloses a disposable diaper in whichthree-dimensional guards each composed of an absorbent material aredisposed at the outside of the an absorbent core in a longitudinaldirection thereof. This diaper also has the same problem as theabove-mentioned disposable diaper.

Another problem of the disposable diaper of Japanese Patent PublicationNo. 05-33630 is that it is not easy for a wearer to put it on becausethis diaper does not deform to the curved configuration of the wearer'sbody at the time of putting it on.

In the disposable diaper of Japanese Patent Publication No. 05-33630,the outside absorbent section is brought into contact with the innerside of the wearer's upper thigh. However, in this disposable diaper,the outside absorbent section is liable to be turned over at an area inthe vicinity of the boundary area between a stomach side region and/orthe back side region where the central absorbent section and the outsideabsorbent section are placed on a same plane and brought into contactwith the wearer and the crotch region where the outside absorbentsection and the central absorbent section are greatly bent, and leak mayoccur through a gap formed between the outside absorbent section and thewearer's skin. Moreover, it is difficult for this disposable diaper tosufficiently fit with the outside absorbent section to the inner side ofthe wearer's upper thigh. In short, in the conventional disposablediapers, sufficient leak-preventive property is not yet realized evenfor those of the type of which an absorbent core is disposed around theleg area.

Recently, it was attempted in order to reduce the economical/laboriousburden in nursing work or the like that an auxiliary absorber is used incombination with a disposable diaper. However, the conventionaldisposable diaper is deteriorated in storability/retainability of theauxiliary absorber and its improvement is demanded.

Japanese Patent Application Laid-Open No. 01-119250, Japanese UtilityModel Application Laid-Open No. 04-67427 and Japanese Utility ModelApplication Laid-Open No. 02-18824 disclose disposable diapers having aside absorbent core. However, even in those disposable diapers, the sideabsorbent core cannot fit to the wearer's leg area sufficiently.Furthermore, even in disposable diapers disclosed in Japanese PatentApplication Nos. 03-121069 and 03-123553, sufficient leak-preventiveproperty cannot be achieved.

SUMMARY OF THE INVENTION

It is, therefore, a first object of the present invention to provide adisposable diaper excellent in leak-preventive property and capable ofsurely preventing leak occurrable around the leg areas.

A second object of the present invention is to provide a disposablediaper excellent in leak-preventive property and excellent instorability/retainability of an auxiliary absorber.

A third object of the present invention is to provide a disposablediaper capable of taking such a curved configuration as being able tofit to the wearer's body at the time of putting it on and therefore,capable of being worn very easily.

A fourth object of the present invention is to provide a disposablediaper capable of fitting its second absorbent core disposed portionhaving a fluid retainability closely to the wearer's skin, excellent infitness to the inguinal area and capable of surely preventing leakoccurrable around the leg areas.

A further object of the present invention is to provide a disposablediaper excellent in storability/retainability of an auxiliary absorber,and excellent in wearability (property of easy application to a wearer)and fitness at the crotch region, in addition to its excellentleak-preventive property.

A still further object of the present invention is to provide adisposable diaper capable of taking the shape of a trunks, excellent inleak-preventive property and designability, and easy to put on or applyto a wearer.

The present invention has achieved the above-mentioned first object byproviding a disposable diaper comprising a fluid-permeable topsheet, afluid-impermeable backsheet and a fluid-retentive absorbent coreinterposed between the topsheet and the backsheet, the disposable diaperbeing formed in a substantially vertically elongated configuration andhaving a stomach side, a back side and a crotch region positionedbetween the stomach side and the back side, wherein a second absorbentcore is disposed at an outside region of each opposite side edge of theabsorbent core at the crotch region along a longitudinal direction ofthe diaper, and an elastic member is disposed at the region where thesecond absorbent core is disposed along a longitudinal direction of thediaper (the “first invention” used hereinafter refers to thisinvention).

Also, the present invention has achieved the above-mentioned secondand/or third object by providing a disposable diaper comprising afluid-permeable topsheet, a fluid-impermeable backsheet and afluid-retentive central absorbent core interposed between the topsheetand the backsheet, the disposable diaper being formed in a substantiallyvertically elongated configuration and having a stomach side, a backside and a crotch region positioned between the stomach side and theback side, wherein a second absorbent core is disposed at an outsideregion of each opposite left (or right) side edge of the centralabsorbent core at the crotch region along a longitudinal direction ofthe diaper, a basis weight of an absorbent core disposed at anintermediate region between the central absorbent core and each of thesecond absorbent cores is smaller than a basis weight of any of theabsorbent cores located at the region where the central absorbent coreis disposed and at the region where each of the second absorbent coresis disposed, and a pair of axes of flexibility are formed on oppositeside portions of the central absorbent core along a longitudinaldirection (the “second invention” used hereinafter refers to thisinvention).

The present invention has achieved the above-mentioned fourth object byproviding a disposable diaper comprising a fluid-permeable topsheet, afluid-impermeable backsheet and a fluid-retentive absorbent coreinterposed between the topsheet and the backsheet, the disposable diaperhaving a stomach side, a back side and a crotch region positionedbetween the stomach side and the back side, leg portion elastic membersbeing disposed in their stretched states at a pair of leg portionsdisposed around the wearer's leg areas, wherein lengthwise opposite endportions of the leg portion elastic members are located at widthwiseoutside areas of side edges of the absorbent core, respectively andcentral portions of the leg portion elastic members are curved in such amanner as to pass a widthwise inner direction of the side edges of theabsorbent core at a crotch region of the diaper, the absorbent core atthe crotch region of the diaper is divided into a pair of secondabsorbent cores located at widthwise outside areas of the leg portionelastic members, respectively and a central absorbent core locatedbetween the pair of second absorbent cores by the pair of leg portionelastic members, and the second absorbent cores are, when in wear, benttowards the backsheet (the “third invention” used hereinafter refers tothis invention).

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more particularly described with referenceto the accompanying drawings, in which:

FIG. 1 is a plan view showing, partly cut-away, a disposable diaperaccording to one embodiment of the first invention;

FIG. 2 is a schematic sectional view taken on line X-X of FIG. 1;

FIG. 3 is a schematic sectional view showing a using state of thedisposable diaper of FIG. 1;

FIG. 4 is a plan view showing, partly cut-away, a disposable diaperaccording to another embodiment of the first invention;

FIG. 5 is a schematic sectional view taken on line X-X of FIG. 4;

FIG. 6 is a plan view (bird's eye view) showing a natural state of thedisposable diaper of FIG. 4 in which its topsheet side (that surfaceside facing the wearer's skin) faces upward;

FIG. 7 is a schematic sectional view showing a using state of thedisposable diaper of FIG. 4;

FIG. 8 is a plan view showing, partly cut-away, a disposable diaperaccording to a further embodiment of the first embodiment;

FIG. 9 is a schematic sectional view taken on line X-X of FIG. 8;

FIG. 10 is a schematic sectional view showing a worn state of thedisposable diaper of FIG. 8;

FIG. 11 is a schematic view showing a trunks-like worn state of thedisposable diaper of FIG. 8;

FIG. 12 is a plan view showing, partly cut-away, a disposable diaperaccording to one embodiment of the second invention;

FIG. 13 is a schematic sectional view taken on line X-X of FIG. 12;

FIG. 14 is a plan view (bird's eye view) showing a natural state of thedisposable diaper of FIG. 12 in which its topsheet side (that surfaceside facing the wearer's skin) faces upward;

FIG. 15 is a schematic sectional view showing a using state of thedisposable diaper of FIG. 12;

FIG. 16 is a perspective view showing a disposable diaper according toone embodiment of the third invention;

FIG. 17 is a partly cut-out plan view showing a developed state of thedisposable diaper of FIG. 16;

FIG. 18 is a schematic sectional view taken on line X-X of FIG. 17;

FIG. 19 is a schematic view showing a worn state of the disposablediaper of FIG. 16; and

FIG. 20 is a sectional view of an important portion showing a disposablediaper according to another embodiment of the third invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be describedhereinafter. A disposable diaper 1 according to a first embodiment ofthe first invention comprises, as shown in FIGS. 1 to 3, afluid-permeable topsheet 2, a fluid-impermeable backsheet 3 and acentral absorbent core 4 as a fluid-retentive absorbent core interposedbetween the topsheet 2 and the backsheet 3, the disposable diaper 1being formed in a substantially vertically elongated configuration.

The topsheet 2 and the backsheet 3 each have an external configurationequal to that of the disposable diaper 1, in which a lengthwise centralportion is constricted. The central absorbent core 4 as an absorbentcore is interposed between the topsheet 2 and the backsheet 3, and ithas a hourglass-like configuration whose lengthwise central portion isconstricted. A waist portion elastic member 13 for forming a waistgather is disposed at a back side region A which is located at the backside of the wearer in wear along a back side waist edge portion (thatportion forming an opening edge portion on a back side of a waistopening portion which is formed when in wear) 11. Fastening tapes 5, 5are disposed at opposite side edges of the back side region A,respectively. Landing zones (not shown) for fixing the fastening tapes5, 5 are disposed at an outer surface of a stomach side region B whichis disposed at the wearer's stomach side when in wear.

A crotch region C in the disposable diaper 1 is a portion which isdisposed at the wearer's crotch in wear and is located between the backside region A and the stomach side region B. Fluid retentive secondabsorbent cores 6, 6 are disposed at outside areas of opposite sideedges 41, 41 of the central absorbent core 4 in the crotch region C insuch a manner as to be spaced apart from the opposite side edges 41, 41,respectively. The second absorbent cores 6, 6 each have a belt-likeconfiguration and are disposed along a longitudinal direction of thediaper 1. More specifically, the second absorbent core 6 isapproximately equal in width over its longitudinal direction in thecrotch region C and is disposed such that its longitudinal direction isaligned with a longitudinal direction of the diaper 1. The secondabsorbent cores 6, 6 are disposed between the back side region A and thestomach side region B and are integrally connected to the centralabsorbent core 4 at opposite end portions 6 a, 6 b thereof,respectively.

As the second absorbent core 6, those conventional ones having variousconstitutions and used as an absorbent core in an absorbent article suchas disposable diaper or the like can be used without any particularlimitation. For example, there can be used an aggregate of hydrophilicfibers composed of a natural material such as, rayon, cellulose or thelike, an aggregate obtained by surface treating synthetic fibers such aspolyethylene, polypropylene or the like, any of those aggregates with awater absorption polymer retained thereby, and the like.

In the disposable diaper of the first invention, an elastic member 8 isdisposed at each region D (see FIGS. 2 and 3) where the second absorbentcore 6 is disposed, along a longitudinal direction of the diaper 1. The“region D” where the second absorbent core 6 is disposed refers to aregion, at the inside of which the second absorbent core 6 is arrangedwhen the disposable diaper is developed and plan viewed as shown inFIG. 1. In the disposable diaper 1 of this embodiment, as shown in FIG.2, plural pieces of elastic members 8 are disposed between the secondabsorbent core 6 and the backsheet 3 in the region D where the secondabsorbent core 6 is disposed. Each elastic member 8 is fixedlysandwichingly held between the backsheet 3 and a fixing sheet 82disposed on the backsheet 3 in an stretched state thereof.

The second elastic member 81 is disposed at an outside area of theregion D where the second absorbent core 6 is disposed in a widthwisedirection of the disposable diaper 1, i.e., in an outside area of theregion D where the second absorbent core 6 is disposed, in a widthwisedirection of the diaper 1 when plan viewed in a developed state of thediaper 1 as shown in FIG. 1, along a longitudinal direction of thediaper 1. One piece each of the second elastic member 81 is disposed atan edge portion of each opposite left (or right) side and is fixedlysandwichingly held, as shown in FIG. 2, between the topsheet 2 and thebacksheet 3 in its stretched state.

The elastic members 8 disposed at the region D and the second elasticmember 81 disposed at the outside region are each arranged over thelength between the back side region A and the stomach side B and inparallel with each other.

The material for forming the various members of the disposable diaper 1of this embodiment will now be described. As the material for formingthe topsheet 2, the backsheet 3, the central absorbent core 4, thefastening tape 5, the waist elastic member 13 and the landing zone (notshown), various kinds of those which have heretofore been used fordisposable diapers can be used without any particular limitation. As theraw material for forming the elastic members 8 and the second elasticmember 81, those of various kinds such as natural rubber, syntheticrubber, spandex and the like can be used. Their shapes may be in theform of thread, belt, film or the like.

The disposable diaper 1 of this embodiment is applied to the wearer foruse in the same manner as the normal disposable diapers. According tothe disposable diaper 1 of this embodiment, since the elastic members 8are disposed at the regions D where the second absorbent cores 6 aredisposed, the skin side surfaces of the regions D where the secondabsorbent cores 6 are disposed nicely fit around the leg areas of thewearer M, as shown in FIG. 3. For this reason, even if urine, etc.should leak out to the side of the central absorbent core 4, they wouldsurely be absorbed by the second absorbent cores 6 without allowing themto reach the side edge portion of the diaper 1. Consequently, leak ofthe excretions, particularly leak of urine around the leg areas, cansurely be prevented.

Moreover, since the central absorbent core 4 and the second absorbentcores 6, 6 are divided from one another at the crotch region C, wrinkleshardly occur to the central absorbent core 4 even if the elastic members8 are contracted. This makes it possible to prevent urine, etc. frommigrating in a lateral direction along the wrinkles which wouldotherwise be formed on the central absorbent core 4. In addition, theabove makes it possible to fully exhibit the absorption capability ofthe central absorptive core 4. Accordingly, leak of urine, etc. can beprevented more effectively.

In the disposable diaper 1 of this embodiment, since the second elasticmembers 81 are disposed at the outside areas of the regions D where thesecond absorbent cores 6, 6 are disposed, the urine absorbed by thesecond absorbent cores 6, 6 can be prevented from leaking from the sideedges.

In the disposable diaper 1 of this embodiment, since the centralabsorbent core 4 and the second absorbent cores 6, 6 are individuallyspaced apart from one another, those regions F, F, which are, when inwear, located between the central absorbent core 4 and the secondabsorbent cores 6 of the diaper 1 are, as shown in FIG. 3, angularlystood up with respect to the wearer's skin surface and are functioned asthree-dimensional barriers for the prevention of leak from those areas.Accordingly, the leak-preventive property, particularly leak-preventiveproperty around the leg areas is further enhanced. Moreover, since theregions F, F located between the absorbent core 4 and the secondabsorbent cores are stood up, a receiving space S having a shape capableof retaining an auxiliary absorber 20 can easily be formed on an innersurface of the disposable diaper 1. Accordingly, the displacementoccurrable to the auxiliary absorber 20 when the auxiliary absorber 20is disposed on the inner surface of the disposable diaper 1, can beprevented effectively. Moreover, the arrangement or replacement of theauxiliary absorber 20 can be carried out very easily and rapidly.

The absorbent core may be disposed at the region F located between thecentral absorbent core 4 and each second absorbent core 6. From the viewpoint of enhancing the standing propensity of the region F, however, theweight per unit area of the region F is preferably ⅔ or smaller than theweight per unit area of the region D where the second absorbent core 6is disposed. The weight per unit area of the region F located betweenthe central absorbent core 4 and each second absorbent core 6 and theweight per unit of the region D where the second absorbent core 6 isdisposed can be obtained as follows, respectively. Test pieces of 1 cm×1cm cut out from the region F and the region D in the disposable diaper,respectively. Then, the weights of the test pieces are measured.

The auxiliary absorber 20 of FIGS. 3 and 7 is a substantially verticallyelongated absorptive pad (auxiliary pad) comprising a fluid-permeabletopsheet 22, a fluid-impermeable backsheet 23 and a fluid-retentiveabsorbent core 24 interposed between the topsheet 22 and the backsheet23. This auxiliary absorber 20 is disposed on an inner surface of thediaper such that its longitudinal direction is aligned with alongitudinal direction of the disposable diaper.

From the view point of exhibiting at least one of the above-mentionedeffects efficiently, the width L (see FIG. 2) of the central absorbentcore 4 is preferably from 5 to 25 cm, the distance L2 between thecentral absorbent core 4 and each second absorbent core 6 is preferablyfrom 0.5 to 10 cm and the width L3 of the second abosrbent core 6 ispreferably from 1 to 10 cm, all at the crotch region C of the disposablediaper 1. Also, from the same view point, the ratio (L1/L) of the widthL1 of the central absorbent core 4 with respect to the smallest width Lof the disposable diaper 1 at the crotch region C is preferably from 0.1to 0.8, the ration (L2/L) of the distance L2 between the centralabsorbent core 4 and each second absorbent core 6 with respect to thesmallest width L of the disposable diaper 1 is preferably from 0.01 to0.3 and the ratio (L3/L) of the width L3 of the second absorbent core 6with respect to the smallest width L of the disposable diaper 1 at thecrotch region C is preferably from 0.02 to 0.3. The dimensions of thevarious portions and the ratios are dimensions obtained by measurementcarried out in a state in which the diaper is developed and planarlyspread as shown in FIG. 1 and the ratios based thereon.

The present invention is not limited to the above-mentioned embodimentand it can be changed or modified in accordance with necessity andwithout departing from the gist of the invention. For example, it isaccepted that the central absorbent core 4 and the second absorbentcores 6 are not spaced apart form each other and that they are adjacentto each other through a slit. Moreover, the second absorbent cores 6, 6may be formed as completely separate bodies from the central absorbentcore 4. In other words, the second absorbent cores 6, 6 and the centralabsorbent core 4 may be divided over the lengthwise entire area of thecentral absorbent core 4.

It is also accepted that an absorptive material having a smaller weightper unit area than the central absorbent core 4 and the second absorbentcores 6 is disposed at the region F between the central absorbent core 4and each second absorbent core 6. For example, it is accepted that anabsorbent core having a small width is laminated on an absorbent corehaving a large width at a widthwise center thereof and opposite sideedge portions of the large width absorbent core are folded back towardsthe surface of the large width absorbent core on which the small widthabsorbent core is laminated, so that a predetermined gap is formedbetween the opposite side edge portions of the small width absorbentcore and the opposite side edge portions of the large width absorbentcore.

The elastic member 8 at the region D where the second absorbent core 6is disposed may be disposed at any part in a thickness direction of theregion D. For example, the elastic member 8 may be disposed between thetopsheet 2 and the second absorbent core 6, or within the secondabsorbent core 6, or at the outer surface of the backsheet 3. Theelastic member 8 is preferable disposed at a location on the more outersurface side of the diaper than the second absorbent core 6. The numberof the elastic members 8 and the second absorbent cores 81 is notparticularly limited. The number may be only one or plural. Theconfiguration, dimension, forming material, etc. of each part of thedisposable diaper can be changed in accordance with necessity. Thedisposable diaper of the present invention is especially suited to beused as a diaper for an adult person. The same effect can be obtainedwhen the present invention is applied to a case where no auxiliaryabsorber is employed.

The disposable diaper of the first invention is excellent inleak-preventive property and is capable of surely preventing the leak(side leak) particularly around the leg areas.

A second embodiment of the first invention will be described withreference to FIGS. 4 to 7. The same explanation as in the firstembodiment will be omitted.

In the disposable diaper 1A according to this embodiment, the secondabsorbent cores 6, 6 are integral with the central absorbent core 4through the absorbent core (the absorbent core disposed at theintermediate region F) having a lower basis weight than the secondabsorbent cores 6, 6. In more detail, the central absorbent core 4 andthe leg absorbent cores 6, 6 are segmented by intermediate regions F, Fprovided with the absorbent cores whose basis weights are lower than thebasis weights of the central and leg absorbent cores 6, 6 and 4 (seeFIG. 5). The regions D where the second absorbent cores 6 are disposedare referred to as the leg absorbent portions D hereinafter.

The topsheet 2 and the backsheet 3 in the disposable diaper 1A accordingto this embodiment are further extended outwardly in the widthwisedirection from the position where the outer edge 61 of the secondabsorbent core 6 is located, and edge flap portions E, E are formed atopposite side edge portions of the diaper 1A by the extended parts ofthe topsheet 2 and the backsheet 3. In the disposable diaper 1Aaccording to this embodiment, a plurality of elastic members 7 a to 7 dare disposed at the edge flap portions E and the leg absorbent portionsD on opposite left and right sides of the diaper 1A along a longitudinaldirection of the diaper. Specifically, two elastic members 7 a, 7 b aredisposed at each edge flap portion E, and two elastic members 7 c, 7 dare disposed at each leg absorbent portion D. The elastic members 7 a, 7b are fixedly sandwichingly held between the topsheet 2 and thebacksheet 3 which constitute the edge flap portion E, and the elasticmembers 7 c, 7 d are fixedly sandwichingly held between the secondabsorbent core 6 and the backsheet 3.

In the disposable diaper according to the second embodiment, thelengthwise shrinkage of the edge flap portion E in the crotch region Con the opposite left and right sides in the longitudinal direction islarger than the lengthwise shrinkage of the leg absorbent portion D. Theshrinkage of the edge flap portion and the shrinkage of the legabsorbent portion D in the longitudinal direction are measured asfollows, respectively.

<Method for Measuring Shrinkage>

The disposable diaper is held in a tensioned state (the state in whichthe elastic members at various portions are stretched and planarlyspread) as shown in FIG. 4. In that state, two points are defined on anouter edge E1 of the edge flap portion E and on an inner side edge D2(the same as on the inner side edge 62 of the second absorbent core 6)of the leg absorbent portion D in the crotch region C, respectively.Then, a shortest distance in a longitudinal direction between the twopoints is represented by a.

Then, the tensioned state is released, and a shortest distance betweenthe two points in a state (natural state) in which no external force isexerted thereto is represented by b.

The shrinkage can be obtained by using the following equation.shrinkage (%)={(a−b)/a}×100

The shrinkage at the outer edge of the edge flap portion is regarded asthe “shrinkage at the edge flap portion E” and the shrinkage at theinner side edge of the leg absorbent portion D is regarded as the“shrinkage at the leg absorbent portion”.

The two points taken on the side edge of the edge flap portion E and onthe inner side edge of the leg absorbent portion D are, in principle,decided by taking one point on a border line between the crotch region Cand the back side region A and another one point on a border linebetween the crotch region C and the stomach side region B. The crotchregion C in the disposable diaper according to this second embodimentrefers to the “two inside regions” of all four regions which areobtained by dividing the disposable diaper into four equal parts in alongitudinal direction of the diaper.

From the view point of enhancing the leak-preventive property, feelduring wear, storability/retainability of the auxiliary absorber,fitness at the crotch region attributable to the enhancement and effectof formability of the leak-preventive barrier formed by bending the legabsorbent portion D, the ration (P/Q) of the shrinkage P of the edgeflap portion E with respect to the shrinkage Q at the leg absorbentportion D is preferably from 1.1 to 3.0, and particularly preferablyfrom 1.3 to 2.0. Also, from the same view point, the shrinkage at theedge flap portion E is preferably from 20 to 70%, and particularlypreferably from 30 to 60%, and the shrinkage at the edge flap portion Eis preferably from 5 to 55%, and particularly preferably from 15 to 45%.

In the disposable diaper 1A, the leg absorbent portion D takes a curvedform, as later described, in its natural state owing to the feature thatthe shrinkage at the edge flap portion E in the longitudinal directionis larger than the shrinkage at the leg absorbent portion D in thelongitudinal direction. Even in a case where no elastic member isdisposed at the edge flap portion E, the leg absorbent portion D can beprotuberatingly curved inward, for example, by applying a highelasticity to the leg absorbent portion D at the area offset to theouter edge thereof and by extremely reducing the rigidity of the edgeflap portion compared with the rigidity of the leg absorbent portion D.However, it is preferred that the elastic member is disposed at the edgeflap portion E from the view point of surely obtaining theabove-mentioned curve, surely exhibiting the enhancement and effect ofthe formability of the leak-preventive barrier,storability/retainability of the auxiliary absorber, etc., fitnessaround the leg areas, and the like, and further enhancing theabove-mentioned effect. In the case where the elastic member is disposedat the edge flap portion E, the shrinking force of the elastic member isnever lost by the shrinkage of the leg absorbent portion D.

In a natural state of the disposable diaper 1A as shown in FIG. 6, theleg absorbent portions D, D are protuberatingly curved inward in awidthwise direction of the diaper. The natural state used herein refersto a state in which the disposable diaper is placed on a horizontalplane and left as it is (the state in which the stretched state of eachelastic member is released) with its topsheet side (that surface sidefacing the wearer's skin) faced upward. In the disposable diaper 1Aaccording to this embodiment, the leg absorbent portions D, D are curvedin such a manner as to form an arc as a whole.

In the disposable diaper 1A according to this embodiment, a shrinkingforce damping region having a predetermined width is formed between thecentral absorbent portion (referred to as the region provided with thecentral absorbent core 4) G and each of the leg absorbent portions D, Dat least in the crotch region. In this embodiment, the intermediateregions F, F are the shrinking force damping regions. The shrinkingforce damping region used herein refers to a region where its lengthwiseinner side edge is small in shrinkage and its lengthwise outer edge islarge when compared with a case in which the region is composed of theleg absorbent portion D. By providing such a shrinking force dampingregion, twisting which would otherwise occur to the central absorbentportion G can be prevented by buffering the shrinking force conveyedfrom the leg flap portion (the region formed by a combination of the legabsorbent portion D with the edge flap portion E). Moreover, bysandwiching the leg absorbent portion D between the edge flap portion Ehaving a large shrinkage and the shrinking force damping region having asmall shrinkage, the curve of the leg absorbent portion D in the crotchregion C can surely be achieved. That is, the leg absorbent portions D,D can surely be curved in such a manner as to be constricted inward atthe nearby area of the shrinking force damping region in the crotchregion C, thereby further enhancing the formability of theleak-preventive barrier and the storability/retainability of theauxiliary absorber, etc. As a method (means) for forming the shrinkingforce damping region, the area between the central absorbent portion Gand each leg absorbent portion D may be composed of (a) a material(plural members are also accepted) having a lower rigidity than the legabsorbent portion D (for example, a absorbent core having a lower basisweight than the second absorbent core 6 is disposed between the topsheetand the backsheet, or not absorbent core is disposed therebetween), or(b) a cushion material such as urethane capable of absorbing theshrinking force (a cushion material may also be disposed between thetopsheet and the backsheet). In this embodiment, an absorbent corehaving a lower basis weight than the central absorbent core 4 and thesecond absorbent core 6 is disposed between the topsheet 2 and thebacksheet 3. The shrinkage at the shrinking force damping region in itslongitudinal direction is obtained by the measuring the shrinkage at theinner side edge of the shrinking force damping region (same as the outeredge G1 of the central absorbent portion G) in the same manner as theabove-mentioned method for measuring the shrinking force at the legabsorbent portion D, etc.

In the case where the shrinking force damping region is provided, anelastic member may be disposed at the shrinking force damping regioninasmuch as the shrinkage of the elastic member is smaller than theshrinkage of the leg absorbent portion D. However, from the view pointof preventing the twisting occurrable to the central absorbent portionG, it is preferred that no elastic member is disposed at the shrinkingforce damping region.

The material of the elastic members 7 a to 7 d are preferably threadrubber, or flat rubber and particularly preferably flat rubber from theview point of shrinkability around the leg areas, machinability andcost.

The disposable diaper 1A according to the second embodiment is appliedto the wearer in the same manner as the normal flat type disposablediapers. According to the disposable diaper 1A of this secondembodiment, since the leg absorbent portions D, D are protuberatinglycurved inward in a widthwise direction of the diaper, the intermediateportions F, F, which are, when in wear, located between the centralabsorbent portion G and the leg absorbent portions D, are, as shown inFIG. 7, angularly stood up with respect to the wearer's skin surface andare functioned as leak-preventive barrier (three-dimensional barriers).Accordingly, this disposable diaper 1A is excellent in leak-preventiveproperty, particularly leak-preventive property around the leg areas.

Moreover, since the intermediate portions F, F located between thecentral absorbent portion G and the leg absorbent portions D are stoodup, pockets S having a recessed form and capable of stably retaining theauxiliary absorber 20 are formed in an inner surface of the disposablediaper 1A. Accordingly, the storability/retainability of the auxiliaryabsorber 20 obtainable when the auxiliary absorber 20 is disposed on theinner surface of the disposable diaper 1 for use in combination, isenhanced. For example, even in case the auxiliary absorber 20 has nofixing means, displacement hardly occurs when in wear. Moreover, thearrangement or replacement of the auxiliary absorber 20 can be carriedout very easily and rapidly.

Moreover, since the leg absorbent portions D, D are fit around the legareas in such a manner as to be protuberatingly curved inward in awidthwise direction of the diaper, the diaper is easy to put on or applyand is excellent in fitness at the crotch region.

In the disposable diaper 1A according to this embodiment, since theelastic members 7 c, 7 c are also disposed at the leg absorbent portionsD along a longitudinal direction of the diaper, the skin side surfacesof the leg absorbent portions D nicely fit around the leg areas of thewearer M, as shown in FIG. 7. For this reason, even if the urine, etc.should leak out to the side of the central absorbent portion, they wouldsurely be absorbed by the leg absorbent portion D without allowing themto reach the side edge portion of the diaper 1. Moreover, since theelastic members 7 a, 7 b are also disposed at the edge flap portion Elocated at an outside area of the leg absorbent portion D, duplex leakpreventing means is formed at the crotch region. Thus, leak of theexcretions from the crotch region can more surely be prevented. Owing tothe feature that the elastic members 7 c, 7 d are disposed at the legabsorbent portion D and the shrinking force damping region (intermediateregion F) is formed between the leg absorbent portion D and the centralabsorbent portion G, the leg absorbent portion D is more surely curvedinward at a peripheral area of the shrinking force damping region in thecrotch region and the formability of the leak-preventive barrier andretainability of the auxiliary absorber such as auxiliary pad areextensively enhanced.

In the case where the elastic members are disposed at the leg absorbentportion D, the elastic members may be disposed at any part in thethickness direction at the regions. From the view point of surelyfitting the specific region to the thigh portion or from the view pointof preventing the leg absorbent portion D from falling towards the innersurface side of the diaper, the elastic members are preferably disposedmore on the outer surface side than the second absorbent core 6 in thethickness direction. At that time, from the view point of preventing thedeterioration of the shrinking force due to detachment of the elasticmembers, it is preferred that a fixing sheet (not shown) is disposed atthe reverse surface side of the second absorbent core in such a manneras to be in abutment with the second absorbent core and the elasticmembers are fixedly sandwichingly held between the fixing sheet and thereverse surface sheet.

In the disposable diaper 1A according to this embodiment, since at leastone pair of fastening tapes as fixing means are disposed at the oppositeleft and right side edge portions of the back side region A and thewaist portion elastic member 13 for forming a waist gather is disposedat an area in the vicinity of the waist opening edge portion 11 in theback side region A, the disposable diaper 1A is very easy to put on orapply. That is, although there is such a fear that when the legabsorbent portion D is curved, the back side flaps forming the oppositeside edge portions in the back side region where the fixing mean isdisposed are slanted towards the crotch region depending on the degreeof the curve, with the result that wearability is lowered, the back sideflaps can be prevented from slanting towards the crotch region C byforming a waist gather at an area in the vicinity of the waist openingedge portion 11 so as to provide expanding/contracting property.Moreover, by disposing the waist gather, it becomes possible not onlythat the effect of leak prevention around the leg areas is enhanced butalso that leak from the waist opening portion is more surely prevented.From the view point of enhancing the effect of leak prevention, thewaist elastic member is preferably disposed at the stomach side regionB, too, as in the back side region A.

From the view point of exhibiting at least one of the above-mentionedvarious effects effectively, the preferable ranges of the width of thevarious portions and the ratio of the width of the various portions inthe crotch region of the disposable diaper 1A, are preferably the sameas those of the disposable diaper 1 according to the first embodiment.

The disposable diaper according to this second embodiment is excellentin storability/retainability of the auxiliary absorber in case the leakpreventability and the auxiliary absorber are employed in combination.Also, the diaper according to the second embodiment is excellentwearability and fitness at the crotch region.

A third embodiment of the first invention will be described hereinafterwith reference to FIGS. 8 to 11. A disposable diaper 1B according tothis third embodiment is designed such that it takes, especially, theshape of trunks when in wear. About those points which are notparticularly described or shown with respect to the third embodiment,the description made with respect to the first or second embodiment isapplied, where appropriate.

The topsheet 2 and the backsheet 3 is the disposable diaper 1B accordingto this third embodiment are extended widthwise outward fromlongitudinal opposite side edges 41, 41 of the central absorbent core 4,and those extended portions form leg flap portions LF, LF atlongitudinal opposite side portions of the diaper. A landing zone 9 forfixing the fastening tapes 5, 5 is disposed at the outer surface of thestomach side region B.

In the disposable diaper 1B according to this third embodiment, a ration(L4/L5) between a smallest width L4 of a crotch region which occupiestwo inside regions of all four regions which are obtained by dividingthe disposable diaper 1B into four equal parts in a longitudinaldirection of the diaper and a largest width L5 of the disposable diaperis from 0.4 to 0.8 and more preferably from 0.55 to 0.75. If the ratio(L4/L5) is smaller than 0.4, there occur such inconveniences that (a)the region where the absorbent core is disposed is too small to obtain asufficient absorption performance and especially when it is tried toform the diaper into the shape of trunks, it becomes difficult tosubstantially obtain the region where the absorbent core is disposed,and that (b) the lug portion of the side flap is likely to open and flapduring conveyance in machining process (deterioration in machining). Incontrast, if the ratio is larger than 0.8, deterioration in wearabilityis unavoidable.

In FIG. 8, one dot chain lines Q1, Q and Q2 denote lines forlongitudinally dividing the disposable diaper 1B into four equal parts.R1 to R4 denote the respective regions obtained by equally dividing thedisposable diaper into four parts in a longitudinal direction. Thecrotch region C is a combination of the region R2 and the region R3. Thedimensions of the various portions and the ratios described in thisspecification are dimensions obtained by measurements carried out in astate (tensioned state) in which the diaper is planarly spread as shownin FIG. 8 and the ratios based thereon unless described otherwisespecifically.

In the disposable diaper 1B according to this embodiment, the largestwidth L5 at the back side region A is preferably larger than the largestwidth L9 at the stomach side region B from the view point ofwearability.

In the disposable diaper 1B, a plurality of leg portion elastic members7 a to 7 d are disposed at the leg flap portions LF, LF located at theoutside areas of the longitudinal opposite side edges 41, 41 of thecentral absorbent core 4 along a longitudinal direction of the diaper.The ratio (L6/L4) between the shortest distance L6 between the innermostedge 71 of the leg portion elastic member and the outermost edge 261 ofthe leg flap portion LF and the shortest width L4 of the crotch region Cis from 0.1 to 0.25. If the ratio (L6/L4) is within the above-mentionedrange, as shown in FIG. 11, that portion, which is located at awidthwise outside area of the inner side edge 71 of the leg portionelastic member in the crotch region C, takes such a shape as to be woundaround the wearer's upper thigh portion in a state in which the diaperis applied to the wearer. By this, the distance of the path for theexcretions to leak therethrough becomes long and so, the effect of theleak prevention is enhanced. Moreover, the disposable diaper accordingto this embodiment is design-wise excellent in outer appearance that cangive a good impression in terms of leak-preventive property to thewearer, the helper, etc. If the ratio (L6/L4) is smaller than 0.1, thediaper becomes unable to take the shape of trunks. In contrast, if theratio (LL6/L4) is larger than 0.25, the disposable diaper becomesdifficult to put on because the leg flap portion is caught by thewearer's upper thigh portion at the time of putting on the diaper.

The leg portion elastic member used herein refers to the elastic memberdisposed at the flap portion LF formed on each opposite side portion ofthe crotch region C along a longitudinal direction of the diaper, andthe innermost edge 71 of the leg portion elastic member used herein,refers, in case only one leg portion elastic member is disposed at theleg flap portion, to the inner edge portion of the leg flap portion in awidthwise direction of the diaper, and in case a plurality of legportion elastic members 7 a to 7 d are disposed at the leg flap portionas this disposable diaper 1B, to the inner edge portion of the legportion elastic member 7 a, which is, among those leg portion elasticmembers 7 a to 7 d, disposed at the innermost side of the diaper, in awidthwise direction of the diaper.

In this disposable diaper 1B, the ratio (L7/L8) between a widthwisedistance L7 between an outermost point P1 of the outer edge 261 of theleg flap portion LF and an innermost point P2 thereof in the crotchregion C and a longitudinal length L8 of the crotch region C is from 0to 0.2. If the ratio (L7/L8) is larger than 0.2, the disposable diaperbecomes difficult to put on because the leg flap portion is caught bythe wearer's upper thigh portion at the time of putting on the diaper.

The outermost point P1 of the outer edge 261 of the leg flap portion LFused herein refers to a point on the outer edge where the distance froma center line (not shown) for dividing the disposable diaper into twoequal parts in a widthwise direction of the diaper becomes longest, andthe innermost point P2 of the outer edge 261 used herein refers to apoint on the outer edge 261 where the distance from the center linebecomes shortest. The widthwise distance L7 between the outermost pointP1 and the innermost point P2 can be obtained by subtracting thedistance from the center line for dividing the disposable diaper intotwo equal parts in a widthwise direction of the diaper to the innermostpoint P2 from the distance from the center line to the outermost pointP1. The ratio (L7/L8) equals 0 (zero) refers to a case where the outeredge 261 of the leg flap portion LF in the crotch region C defines alinear line in parallel with a longitudinal direction of the diaper overthe lengthwise entire area of the crotch region C. A diaper of theabove-mentioned form is also included in one preferred embodiment of thepresent invention.

In the disposable diaper 1B according to the third embodiment, theoutermost point P1 of the outer edge 261 of the leg flap portion LF inthe crotch region C is located at the back side region (the aboveregions R1 and R2) of all the two regions obtained by dividing thedisposable diaper 1B into two equal parts in a longitudinal direction ofthe diaper.

In the disposable diaper 1B according to this embodiment, although twopairs of fastening tapes 5, 5 are employed, one pair, or three pairs ormore of fastening tapes may be employed. However, in the case where onepair of fastening tapes are employed, it is preferred that the waistportion elastic member 13 for forming the waist gather is disposed alongthe back side waist edge portion 11 in order to prevent thedeterioration of the fitness. At the time of measuring the largest widthof the disposable diaper 1B, the measurement is carried out in a statein which the fastening tape 5 is bent inward as shown in FIG. 8.

In the disposable diaper 1B according to this embodiment, the secondabsorbent cores 6, 6 each having a predetermined width are disposed atleast at a part of the leg flap portions LF in the crotch region C. Morespecifically, the fluid retentive second absorbent cores 6, 6 aredisposed at outside areas of opposite side edges 41, 41 of the centralabsorbent core 4 in the crotch region C in such a manner as to be spacedapart from the opposite side edges 41, 41 respectively. The secondabsorbent cores 6, 6 each have a belt-like configuration and aredisposed along a longitudinal direction of the diaper 1. The secondabsorbent core 6 is approximately equal in width over its longitudinaldirection in the crotch region C and is disposed such that itslongitudinal direction is aligned with a longitudinal direction of thediaper 1.

The second absorbent cores 6 may be disposed at least at a part of theleg flap portions Lf. However, since the excretions migrating over thecentral absorbent core 4 are likely to reach not only the leg flapportions LF, LF in the crotch region C but also the flap portions in theback side and stomach side regions when the diaper wearers excreteurine, etc. while lying on their side, the second absorbent cores 6 arepreferably disposed over at least one of the stomach side flap portion(that portion located at an outside area of each opposite left (orright) side edge of the central absorbent core 4 in the stomach sideregion B) and the back side flap portion (that portion located at anoutside area of each opposite left (or right) side edge of the centralabsorbent core 4 in the back side region A) from the crotch region C,and more preferably disposed over both the stomach side flap portion andthe back side flap portion from the crotch region C.

In the disposable diaper of the present invention, the topsheet 2disposed on the central absorbent core 4 is extended widthwise outwardfrom the opposite side edges of the central absorbent core 4 and theextended portions of the topsheet 2 preferably cover at least the inneredges of the second absorbent cores 6, 6, respectively, and in order toprevent the fluid from oozing out from the second absorbent cores 6, 6the outer edges of the second absorbent core 6 is preferably coveredwith a fluid-impermeable sheet.

According to the disposable diaper 1B of the third embodiment, since theratios (L4/L5), (L6/L4) and (L7/L8) are within the above-mentionedspecific ranges, respectively, the diaper can take the trunks-likeshape, as shown in FIG. 11, during wearing the diaper. Thus, the leakpreventing effect and design can be enhanced. Moreover, there is no suchan inconvenience that the diaper is difficult to put on or apply asoften experienced in the conventional trunks-like diaper.

In the disposable diaper 1B according to the third embodiment, since theleg portion elastic members 7 a, 7 b are not disposed at the regions Fbetween the central absorbent core 4 and the second absorbent cores 6,6, the shrinking force of the leg portion elastic members disposed atthe widthwise outside areas of the regions F is absorbed and damped bythe regions F. Accordingly, this absorbent diaper is excellent in fit,absorbent performance, and in pad storability in case an absorption padis used in combination.

From the view point of exhibiting the enhancement of fitness and theeffect of leak prevention more significantly, the width L3 of eachsecond absorbent core 6 is preferably from 1 to 10 cm and particularlypreferably from 2 to 5 cm, and the ratio (L3/L4) between the width L3 anthe smallest width L4 of the crotch region C is preferably from 0.02 to0.3. Also, the width L1 of the central absorbent core 4 is preferablyfrom 5 to 25 cm, and the ratio (L1/L4) between the width L1 and thesmallest width L4 of the crotch region C is preferably from 0.1 to 0.8.

The layer structure of the leg flap portion is not limited to those ofthe above-mentioned embodiment. For example, instead of the topsheet 2and/or backsheet 3, the layer structure of the leg flap portion may beconstituted of a single or a plurality of other sheets, or besides thetopsheet and backsheet 2, 3, other sheets and non-sheets may beemployed.

As a method for forming the central absorbent core and the secondabsorbent core in the first invention, there can be considered (a) thecentral absorbent core and the second absorbent core are supplied asseparate bodies, (b) a slit is formed in or an emboss is formed on thecentral absorbent core over its entire length or at least at the crotchregion in a longitudinal direction thereof, (c) a region having a smallweight per unit area is formed at the central absorbent core over itsentire length or at least at the crotch region in a longitudinaldirection thereof, (d) the widthwise opposite end portions of absorptionmaterials having a wide width are folded back towards the surface facingthe inner surface side of the diaper and laminated, and then, absorptionmaterials having a narrow width are laminated on a central portionbetween the two laminated portions so that a prescribed gap is formedbetween the inner edge portions of the laminated portions and the aabsorption materials, and the like.

Another preferred embodiment of the first invention includes a diaperhaving the central absorbent core 4 and the second absorbent cores 6, 6which are integrally connected with each other and segmented by anembossing line formed along the longitudinal direction of the diaper.

When the central absorbent core and the second absorbent core are formedin the manner as mentioned above, the regions F become bent regions andthe second absorbent core is surely bent towards the upper thigh,thereby enhancing the fitness at the crotch upper thigh portion,leak-preventive property and trunks-like outer appearance. In the above(d) method, the portion composed of the two-layer absorption materialsformed on the central portion constitutes the central absorbent core,and the portion composed of the two-layer absorption materialsconstitutes the second absorbent core.

Preferred embodiments of the second invention will be describedhereinafter. A disposable diaper 1C as one embodiment of the secondinvention has, as shown in FIGS. 12 to 15, the same basic constructionas the above-mentioned disposable diaper 1B. Accordingly, likecomponents are denoted by like reference numerals and descriptionthereof is omitted. About those points which are not particularlydescribed, the description made with respect to the disposable diaper 1Bis applied, where appropriate.

In the disposable diaper 1C of the second invention, the secondabsorbent cores 6, 6 are disposed at the outside areas of the oppositeside edges 41, 41 of the central absorbent core 4 in the crotch region Calong a longitudinal direction of the diaper. The second absorbent cores6, 6 according to this embodiment are disposed in such a manner as to bespaced apart from the opposite side edges 41, 41 of the centralabsorbent core 4. They are in the form of belt and are fixedlysandwichingly held between the topsheet 2 and the backsheet 3 extendingwidthwise outward from the opposite side edges in a longitudinaldirection of the central absorbent core 4 such that their longitudinaldirection is aligned with the longitudinal direction of the diaper.

In this second invention, although it suffices that the second absorbentcores 6 are provided to at least one part in the longitudinal directionin the crotch region C, they are preferably disposed from the crotchregion C over to at least one of the back side region A and the stomachside region B. It is more preferable that the second absorbent cores 6are disposed from the crotch region C over to both the back side regionA and the stomach side region B as in this embodiment.

In the disposable diaper 1C of the second invention, the basis weights(basis weights of the absorbent core per unit area) in the intermediateregions F, F located between the central absorbent core 4 and the secondabsorbent cores 6, respectively are smaller than the basis weights ofthe absorbent cores in the region G where the central absorbent core 4is disposed and in the regions D where the second absorbent cores 6 aredisposed. The basis weight of the intermediate regions F may be 0(zero). The region G where the central absorbent core 4 is disposed andthe regions D where the second absorbent cores 6 are disposed, usedherein refer to those regions where the central absorbent core 4 or thesecond absorbent cores 6 are disposed at the interior of the disposablediaper in a thickness direction, when the diaper is plan viewed in atensioned state (the state in which the elastic members at variousportions are stretched and planarly spread) as shown in FIG. 12.

The basis weight per unit area of the region G where the centralabsorbent core 4 is disposed, the basis weight of the absorbent cores inthe regions D where the second absorbent cores 6 are disposed, and thebasis weight per unit of the absorbent cores in the intermediate regionsF located between the central absorbent core and the second absorbentcores can be obtained as follows, respectively. Test pieces of 1 cm×1 cmare cut out from the regions G, D, F, respectively. Then, the weights ofthe test pieces are measured and converted into basis weights (g/cm²).In this invention, the “absorbent core” refers to a layer adapted toabsorb/retain fluid, such as water absorption polymer, pulp and mount,and it does not include the topsheet 2 and the backsheet 3. Accordingly,in the case where the intermediate regions F are composed of only thetopsheet 2 and the backsheet 3, the basis weight of the absorptive coresin the intermediate region is 0 (zero).

In the disposable diaper 1C of the second invention, one pair of axes offlexibility 48, 48 serving as bent portions (bend lines) at the time ofbending the central absorbent core in the widthwise direction, areformed on the opposite side portions of the absorbent, core 4 at leastat one part of the diaper in the longitudinal direction, along thelongitudinal direction of the central absorbent core 4.

In this invention, the pair of axes of flexibility 48, 48 may be formedon the central absorbent core 4 in the crotch region C or on the centralabsorbent core 4 in the back side region A and/or stomach side region B.The pair of axes of flexibility 48, 48 are preferably formed from thecrotch region C over to the back side region A and/or stomach sideregion B, and more preferably formed all over the back side region A,the crotch region C and the stomach side region B.

In the case where the axes of flexibility 48, 48 are disposed at thecentral absorbent core 4 in the crotch region C, the opposite side edgeportions of the central absorbent core 4 are easily stood up along theaxes of flexibility 48, 48 and the central absorbent core 4 is formedinto a recessed shape as shown in FIG. 15. Moreover, since the oppositeside edge portions of the central absorbent core 4 having a large basisweight are stood up, the intermediate regions F having a smaller basisweight than the region G where the central absorbent core 4 is disposed,are also easily stood up. Since the opposite side edge portions of thecentral absorbent core 4 which are stood up as mentioned above and theintermediate regions F connected thereto are functioned as aleak-preventive barrier (three-dimensional barrier), there can beobtained a disposable diaper having an excellent leak-preventiveproperty.

Moreover, since the opposite side edge portions of the central absorbentcore 4 and the intermediate regions F are stood up, recessed pockets Scapable of stably retaining an auxiliary absorber 20 such as anauxiliary pad, are formed on the inner surface of the disposable diaper1C. Accordingly, the storability/retainability of the auxiliary absorber20 can be enhanced in the case where the auxiliary absorber 20 isdisposed on the inner surface of the disposable diaper 1C and used incombination. By this, even in the case of the auxiliary absorber 20having no fixing means, no positional displacement occurs during wearingthe diaper. Moreover, the arrangement or replacement of the auxiliaryabsorber 20 can be carried out very easily and rapidly. The auxiliaryabsorber 20 shown in FIG. 15 is an absorptive pad having theabove-mentioned construction and is disposed within the pocket S withits longitudinal direction aligned with the longitudinal direction ofthe disposable diaper 1C. Moreover, since the basis weight of theabsorbent cores at the regions D where the second absorbent cores aredisposed, is larger than the basis weight of the absorbent cores in theintermediate regions F, the second absorbent cores are bent outwardly inthe widthwise direction and there occurs no such inconvenience that thesecond absorbent cores are fallen towards the inner side at the time ofputting on the diaper.

In the case where the axes of flexibility 48, 48 are disposed at thecentral absorbent core 4 in the crotch region C, it is preferred thatthe axes of flexibility 48, 48 are formed at least at the centralportion of the crotch region C and their length in the longitudinaldirection is 50% or more, and particularly 80% or more based on theentire length of the crotch region C in the longitudinal direction. Inthe case where the axes of flexibility 48, 48 are not disposed at thecentral absorbent core 4, the standability of the intermediate regionsF, F are lowered and the formability of the leak-preventive barrier islowered. If the basis weight of the absorbent cores in the intermediateregions F, F is larger than the basis weight of the absorbent core inthe region G where the central absorbent core 4 is disposed, thestanding up of the side edge portions of the central absorbent core isjeopardized, and the formation of the pocket by the central absorbentcore and the formation of the leak-preventive barriers at theintermediate regions is jeopardized.

In the case where the pair of axes of flexibility 48, 48 are formed atthe central absorbent core 4 in the back side region A and/or stomachside region B, the back side region A and/or the stomach side region Bof the diaper are brought into a curved configuration so as to be nicefit to the wearer's body contour at the time of putting on the diaper,and therefore, the diaper is very easy to put on or apply. In thedisposable diaper according to this embodiment, the pair of axes offlexibility 48, 48 are formed all over the back side region A, thecrotch region C and the stomach side region B, and the respective axesof flexibility 48 are formed on the central core 4 over the lengthwiseentire area thereof.

The axes of flexibility of the second invention may be properly selectedfrom those in which in a state (natural state) where no external forceis exerted to the diaper, the central absorbent core is bent at the axesof flexibility and the opposite side edge portions of the centralabsorbent core are located at an upper position than the central portionin a widthwise direction of the central absorbent core. As a method forforming them, there can be listed (a) a part of the central absorbentcore is compressed and the compressed part of the central absorbent coreserves as the axes of flexibility, (b) a part of the central absorbentcore is melted by heat treatment and the melted portion serves as theaxes of flexability, (c) a slit is formed in the central absorbent coreover a widthwise entire area thereof or a cut is formed in the centralabsorbent core at only a part of the widthwise entire area thereof, andthat portion where the slit or cut is formed serves as the axes offlexibility, (d) the central absorbent core is folded back to bond theouter surface sheets together and the portion bent at that time servesas the axes of flexibility, (e) regions each having a different rigidity(different in basis weight, or the like) are disposed in a widthwisedirection of the absorbent core and the borderline between the differentrigidities serves as the axes of flexibility, and the like.

The axes of flexibility 48, 48 in the disposable diaper 1C according tothis embodiment are formed by folding back the opposite side edgeportions of the central absorbent core 4 towards the inner surface sideof the diaper along a longitudinal direction of the diaper and the bentportion is compressed by embossing, pressing machine or the like. Priorto this compressing treatment, emboss treatment is applied to at least apart of the central absorbent core along its longitudinal direction or ahot melt type adhesive agent is applied to preliminarily harden thatpart of the central absorbent core so that at least a part of thebending portion occupies the hardened portion. By doing so, theformability, retainability of the axes of flexability are furtherenhanced.

The axes of flexibility are formed at a position of preferably from 5 to70 mm and more preferably from 5 to 50 mm from the side edges 41 of thecentral absorbent core 4 inward over the longitudinal entire length. Thebasis weight of the region G where the central absorbent core 4including the axes of flexibility are disposed is preferably 550 g/m² orsmaller and more preferably 300 g/m². If the basis weight of the regionG is 300 g/m2 or smaller, the opposite side edge portions of the centralabsorbent core 4 are easy to carry out and the restoring force isreduced. Accordingly, a folded-back shape (the shape bent at the axes offlexibility) is easily retained on the central absorbent core. If thebasis weight of the absorbent core 4 including the axis of flexibilityportion is 550 g/m² or smaller, the axes of flexibility are easy to formand the folded-back shape is easy to retain. Accordingly, theformability of the leak-preventive barrier is enhanced.

In the disposable diaper of the second invention, the central absorbentcore 4 and the second absorbent cores 6, 6 may be separate bodies.However, it is preferred from the view point of simplicity of machiningprocess that the central absorbent core 4 and the second absorbent cores6, 6 are integrally formed. In this case, the boundaries between theintermediate region F and the regions C and D are established asfollows.

In the case where the basis weight of the absorbent core is abruptlychanged in its widthwise direction (same direction as the widthwisedirection of the diaper), the boundaries between the absorbent cores ofthe intermediate regions and the central absorbent core and secondabsorbent cores are the line extending along the longitudinal directionwhere the basis weight of the absorbent core is clearly changed in thewidthwise direction. In the case where the basis weight of the absorbentcore is gently changed in its widthwise direction(same as the widthwisedirection of the diaper), the boundaries between the absorbent cores inthe intermediate regions and the central absorbent core are the linepassing through the widthwise center between the line where the basisweight along the longitudinal direction is smallest (when the portionshaving the same basis weight exist over a plane, the line closest to theinner edge) and the line (when the portions having the same basis weightexist over the plane, the line closest to the outer edge) on the centralabsorbent core 4 where the basis weight is largest, while the boundariesbetween the absorbent cores in the intermediate regions and the secondabsorbent cores are the line passing through the widthwise centerbetween the line where the basis weight is smallest (when the portionshaving the same basis weight exist over a plane, the line closest to theouter edge) and the line (when the portions having the same basis weightexists over a plane, the line closest to the inner edge). The regionshaving a prescribed width sandwiched between two boundaries establishedin this way serve as the intermediate region.

In the second invention, the ratio (the former/the latter) between thebasis weight of the absorbent cores in the intermediate region F and thebasis of the absorbent core in the region G where the central absorbentcore 4 is disposed is preferably from 0 to 0.5. Also, the ratio (theformer/the latter) between the basis weight of the absorbent cores inthe intermediate regions F and the basis weight of the absorbent coresin the regions D where the second absorbent cores 6 are disposed ispreferably from 0 to 0.5. The difference of the basis weights of theabsorbent cores between the region G and the intermediate regions F andthe difference of the basis weights of the absorbent cores between theregions D and the intermediate regions F are preferably at least 100g/m² or larger and particularly preferably 200 g/m² or larger.

In the disposable diaper of the second invention, elastic members aredisposed along a longitudinal direction of the diaper at the regions Dwhere the second absorbent cores 6 are disposed and/or at edge flapportions E which are formed at widthwise outside areas of the regionswhere the second absorbent cores 6 are disposed and where no absorbentcores exist, and the basis weight of the absorbent cores in theintermediate regions F is preferably ⅔ or smaller the basis weight ofthe absorbent cores in the regions D where the second absorbent cores 6are disposed.

Two elastic members 7 a, 7 b are disposed at each edge flap portion E inthe disposable diaper 1C according to this embodiment, and two elasticmembers 7 c, 7 d are disposed at each region D where the secondabsorbent core 6 is disposed.

In the disposable diaper 1C according to this embodiment, since theelastic members 7 c, 7 d are disposed along a longitudinal direction ofthe diaper at each region D where the second absorbent core 6 isdisposed, the skin side surface of the region D nicely fits around theleg area of the wearer M as shown in FIG. 15. Accordingly, even ifurine, etc. should leak out to the side of the central absorbent core 4,they are surely captured by the second absorbent cores 6 without beingallowed to reach the side edge portions of the diaper. Moreover, sincethe elastic members 7 a, 7 b are also disposed at the edge flap portionsE which are located at the outside areas thereof, duplex leak-preventivemeans is formed at the crotch region and thus, leak of excretionsoccurrable from the crotch region can more surely be prevented.

In the case where the elastic members 7 c, 7 d are disposed at eachregion D where the second absorbent core is disposed and the basisweight of the absorbent cores in the intermediate regions F is set to ⅔or less the basis weight of the absorbent cores in the regions D wherethe second absorbent cores 6 are disposed, the intermediate regions areeasily stood up to form the leak-preventive barrier by the shrinkingforce occurrable when the second absorbent cores 6, 6 and/or the legflap portions E are shrunk. Accordingly, the storability/retainabilityof the auxiliary pad, etc. and the leak-preventive property are enhancedextensively. In the case where the basis weight of the absorbent coresin the intermediate regions F and the basis weight of the absorbentcores in the regions where the second absorbent cores 6 are disposedhave the above-mentioned relationship, the regions D where the secondabsorbent cores 6 are disposed are surely bent outward by the weightdifference. Accordingly, there can surely be prevented such aninconvenience that the regions D are fallen towards the inner side atthe time of putting on the diaper. The basis weight of the absorbentcores in the intermediate regions is preferably 1/20 or more the basisweight of the absorbent cores of the regions D where the secondabsorbent cores 6 are disposed.

In the disposable diaper 1C according to this embodiment, as shown inFIG. 12, the axes of flexibility 48, 48 are formed at the outer tworegions H, H of all the four regions obtained by dividing the centralabsorbent core 4 into four equal parts in a widthwise direction. Owingto this construction, even in the case where the opposite side edgeportions of the central absorbent core 4 are completely folded back ontothe inner surface of the diaper along the axes of flexibility 48, 48 itnever happens that the inner surface of the region G where the centralabsorbent core 4 is disposed is blocked with the folded-back portionbecause the opposite side edge portions of the central absorbent core 4are not overlapped with each other. Thus, the problem of lowering of theabsorptive performance does not occur. Moreover, by preventing the sideedge portions of the central absorbent core from being overlapped witheach other, the pack volume can be reduced at the time of compressioncharging the diaper into a packing bag for packing.

The axes of flexibility 48, 48 of the disposable diaper 1C according tothis embodiment is formed by folding back the opposite side edgeportions 41, 41 of the central absorbent core 4 towards the innersurface side of the diaper along a longitudinal direction of the centralabsorbent core 4 and compressing the folded back portions. The axes offlexibility 48, 48 are formed over the entire length in the longitudinaldirection of the central absorbent core 4. By this, the axes offlexibility can be formed over the entire length of the centralabsorbent core 4 easily and without a need of extensive reconstructionof the conventional equipment. Moreover, the manufacturing cost can bereduced.

In the disposable diaper of the second invention, the shrinkage in alongitudinal direction of the edge flap portions E in the crotch regionC in the longitudinal opposite left and right sides is preferably largerthan the shrinkage in a longitudinal direction of the regions (legabsorbent portions) D where the second absorbent cores 6 are disposed.The longitudinal shrinkages of the edge flap portion E and the regions(leg absorbent portions) D where the second absorbent cores 6 aredisposed are measured by the above-mentioned method.

Preferred ranges of the shrinkage Q at the leg absorbent portion D (legabsorbent portion) provided with the second absorbent core 6, theshrinkage P at the edge flap portion E and the ratio (P/Q) are the sameas those of the disposable diaper 1A from the same view points as those.

By making the shrinkage in the longitudinal direction of the edge flapportion E in the crotch region C larger than the shrinkage in thelongitudinal direction of the region D where the second absorbent core 6is disposed, the second absorbent cores 6, 6 in the crotch region C are,in a natural state, protuberatingly curved widthwise inwards of thedisposable diaper easily and surely without losing the shrinking forceof the elastic members 7 a, 7 b disposed at the edge flap portion E byshrinkage of the region D where the second absorbent core 6 is disposed(see FIG. 14). Owing to this construction, the disposable diaperaccording to this embodiment is more excellent in leak-preventiveproperty, storability/retainability of the auxiliary absorber and alsoexcellent in the fitness at the crotch portion. The first and secondinventions can be applied to a shorts type diaper, too. In that case,the side seal portions at the opposite side portions of the diaper arepeeled off and the diaper is then developed. The shrinkage, dimensions,etc. of the various portions are measured in that state, and the curvedcondition of the second absorbent cores is determined in a naturalstate.

From the view point of exhibiting at least one of the above-mentionedeffects efficiently, the width of each portion and the ratio of thewidth of each portion in the crotch region C of the disposable diaper 1Care preferably same as the above-mentioned disposable diapers 1, 1A.

The first and second inventions are not limited to the above-mentionedvarious embodiments and they can be changed and modified in accordancewith necessity and without departing from the gist of each invention.For example, as one form of arrangement of the second absorbent cores 6,the central absorbent core 4 and the second absorbent cored 6 may bearrange adjacent to each other through a slit and without being spacedapart from each other, or the second absorbent cores 6 may be integrallyconnected to the central absorbent core 4 in the back side region Aand/or stomach side region B. The second-mentioned form is excellentfrom the view point of further enhancement of the leak-preventiveproperty in the back side region A and/or stomach side region B.

It is preferred for the reason of simplification of the machiningprocess that the central absorbent core and the second absorbent coresare integrally formed. As a method for integrally forming the centralabsorbent core and the second absorbent cores, it is preferred that thecentral absorbent core, the shrinking force damping region and thesecond absorbent cores are simultaneously formed by (a) applying a lowdensity region in a widthwise direction, (b) a slit or the like isformed in the longitudinal direction, and (c) an absorbent core having asmall width is laminated on an absorbent core having a large width at awidthwise center thereof and opposite side edge portions of the largewidth absorbent core are folded back towards the surface of the largewidth absorbent core on which the small width absorbent core islaminated, so that a predetermined gap is formed between the oppositeside edge portions of the small width absorbent core and the oppositeside edge portions of the large width absorbent core.

The central absorbent core and/or the second absorbent cores arepreferably applied thereon with an emboss which is either parallel to orslanted to the longitudinal direction of the respective absorbent cores.By applying the emboss to those absorbent cores, the absorbent cores canbe used efficiently because the absorbent cores can be prevented frombeing twisted and fluid such as urine, etc. are dispersed in thelongitudinal direction along the line of the emboss.

The outer edges of the second absorbent cores are preferably coveredwith a water-repellent sheet in order to prevent urine, etc. fromleaking out from the outer edges of the second absorbent cores.Moreover, a three-dimensional gather may be arranged for the purpose ofthe enhancement of the effect of leak prevention. The position forarranging the three-dimensional gather is not particularly limited. Itis preferred that a fixing end is formed on the central absorbent core 4and the sheet material extended more outward in a widthwise direction ofthe diaper than the fixing end and adapted to form the three-dimensionalgather does not overlie the second absorbent core. It is more preferredthat the sheet material does not cover the outer edge of the centralabsorbent core. In this invention, since the leak-preventive barrier isformed by the leg absorbent portions being curved and bulged, it is notparticularly necessary to provide the three-dimensional gather. In thecase where the three-dimensional gather is provided, a fluid-permeableand fluid-impermeable material can be used. In order to prevent thereduction of the hydrophilic region at the fixing portion, etc., it ispreferred that a fluid-permeable material is used.

Also, it is preferred that a color(s) is applied to the region (legabsorbent portion) D where the second absorbent core is disposed, and/oran area in the vicinity of the region D along the longitudinaldirection, so that those regions can visually be discriminated form thecentral region sandwiched between the two colored regions. In contrast,the central region may be colored. By this, much labor required forpositioning at the time of putting on the diaper and for positioning theauxiliary absorber for wearing can be improved extensively. As acoloring method, there can b e listed, for example, (a) the oppositesides of the topsheet are colored, (b) the opposite side portions of anupper layer mount of the absorbent core are colored, (c) a lower layermount of the absorbent core is colored and then, the opposite sideportions of the mount are folded back towards the outer surface side,and the like. The disposable diaper of this invention is especiallysuited to be used as a diaper for an adult person. Also, it can be usedwithout a need of a combined use of the auxiliary absorber. Moreover,the disposable diaper of this invention may be an auxiliary absorber.

No elastic members may be disposed at the region D where the secondabsorbent core 6 is disposed and/or the edge flap portions E in thesecond invention. The number of the elastic members disposed at the legabsorbent portions D and/or the edging flap portions E, may be only one,or three or more. The shape, dimensions, forming material, etc. of thevarious portions of the disposable diaper can be changed in accordancewith necessary.

According to the second invention, there can be provided a disposablediaper which is excellent in leak-preventive property andstorability/retainability of the auxiliary absorber. Also, according tothe second invention, there can be provided a disposable diaper in whichthe diaper takes a curved configuration nicely fitting to the wearer'sbody contour and which is very easy to put on or apply.

Preferred embodiments of the third invention will be describedhereinafter. A disposable diaper 1D as one embodiment of the thirdinvention is a shorts type disposable diaper. As shown in FIGS. 16 to18, the disposable diaper 1D comprises an absorbent main body 110including a fluid-permeable topsheet 2, a fluid-impermeable backsheet 3and a fluid-retentive absorbent core 40 interposed between the topsheet2 and the backsheet 3, and an outer layer body 120 located at an outsidearea (outer surface side of the diaper) of the absorbent main body 110and to which the absorbent main body 110 is fixedly joined. Oppositeside edges A1, A2 of a stomach side region A which is arranged on thewearer's stomach side at the time of putting on the diaper and oppositeside edges B1, B2 of a back side region B which is arranged on thewearer's back side at the time of putting on the diaper are joinedtogether by known joining means such as heat sealing, high frequencysealing, ultrasonic sealing and the like, thereby forming a waistopening portion 15 and one pair of leg opening portions 16, 16.

The absorbent main body 110 has a vertically elongated squareconfiguration. The absorbent main body 110 is joined to a widthwisecentral portion of the outer layer body 120 with its longitudinaldirection aligned with a direction (up and down direction of FIG. 17,hereinafter sometimes referred to as the “longitudinal direction” of thediaper) for connecting the stomach side region A and the back sideregion B of the disposable diaper 1D which is in a developed state. Theabsorbent core 40 has an outer contour of a vertically elongated squareconfiguration which is generally same as the absorbent main body 110,and is fixedly sandwiched between the topsheet 2 and the backsheet 3.

A plurality of waist elastic members 151 for forming a waist gather arearranged at predetermined intervals along an opening edge portionthereof, and a substantially continuous annular waist gather is formedover an entire circumference of the waist opening portion 15.

A leg portion elastic member 161 for forming leg gather is disposed inits stretched state on each of one pair of leg portions 60, 60 arrangedaround the wearer's leg area. Each leg portion elastic member 161comprises a first elastic member 161 a disposed over the crotch region Cfrom the stomach side region A and a second elastic member 161 bdisposed over the back side region B from the crotch region C. The firstelastic member 161 a and the second elastic member 161 b are overlappedwith each other at the crotch region C and function substantially sameas a continuous elastic member.

The absorbent core 40 at the diaper crotch region (region disposed atthe wearer's crotch in wearing) C is sectioned at least at one part ofits longitudinal direction (same direction as the longitudinal directionof the diaper) into one pair of second absorbent cores 143, 143 whichare located at widthwise outside areas of the locations of the legportion elastic members 161 and a central absorbent core 142 which islocated between the pair of second absorbent cores 143, 143, by the legportion elastic members 161, 161. The central absorbent core 142 islocated at a widthwise center of the diaper crotch region C, while thesecond absorbent cores 143, 143 are located at opposite left and rightsides of the central absorbent core 142.

In this embodiment, the absorbent core 40 at the diaper crotch region Cincludes one pair of low rigidity regions 4A, 4A which are spaced apartfrom the opposite left and right side edges 141, 141 in a longitudinaldirection of the absorbent core 40 and which are lower in rigidity thanother parts. The pair of low rigidity regions 4A, 4A are formed alongthe longitudinal direction of the absorbent core 40. The secondabsorbent core 143 sectioned by the leg portion elastic member 161 isbent at its topsheet 2 side outward in a widthwise direction of thediaper by the elastic shrinking force of the leg portion elastic member161 at the time of putting on the diaper. That is, as shown in FIG. 19,the second absorbent core 143 is bent towards the backsheet 3 sideserving the part of arrangement of the leg portion elastic member 161 asa bending line. By this, since the fluid-retentive absorbent core isdisposed along the leg part of the wearer, the leak-preventive propertyis high compared with the conventional one.

The leg portion elastic member 161 is, as shown in FIG. 17, disposed insuch a manner as to be curved in a generally arc shape. One end portion162 of each leg portion elastic member 161 located on the stomach regionA side and the other end portion 163 located on the back side region Bare located at the widthwise outside areas of the side edge of theabsorbent core 40. A central part 164 of each leg portion elastic member161 passes a widthwise inside area of the side edge 141 of the absorbentcore 40 in the diaper crotch region C. More specifically, the centralpart 164 of each leg portion elastic member 161 passes the low rigidityregion 4A. The expression “the central part 164 of each leg portionelastic member 161 passes the low rigidity region 4A” includes a case inwhich the central part 164 of each leg portion elastic member 161 passesthe thickness-wise outer surface Q side of the absorbent core 40, forexample, the low rigidity region 4A passes a part corresponding to thelow rigidity region A within the outer layer body 20 as in thisembodiment. The central part 164 of each leg portion elastic member 161refers to whole area of the leg portion elastic member 161 onlyexcepting its opposite end portions 162, 163. It suffices that at leasta part of the central part 164 passes a widthwise inside area of theside edge 141 of the absorbent core 40 in the crotch region C.

From the view point of surely enhancing the leak-preventive property, atleast the area in the vicinity of the central portion of each legportion elastic member 161 which divides the longitudinal direction ofthe leg portion elastic member 161 into two equal parts is located inthe low rigidity region 4A. The length (length measured along thelongitudinal direction of the diaper) L10 of the leg portion elasticmember 161 passing the inside of the low rigidity region 4A ispreferably from 10 to 50% and particularly preferably from 20 to 40%with respect to the entire length L11 of the absorbent core 40, andpreferably from 5 to 40% and particularly preferably from 15 to 30% withrespect to the longitudinal length L12 of the diaper 1D. The variousvalues are based on the dimensions measured in a state that the joinedside parts of the diaper are all peeled off each other and the diaper isdeveloped and held in a tensioned state (the elastic members of thevarious parts are stretched, see FIG. 17).

In the disposable diaper 1D according to this embodiment, since the legportion elastic member 161 is disposed in the manner as described above,a gap is hardly formed between the second absorbent core disposedportion (region where the second absorbent core 143 is disposed) 111 andthe wearer's skin even at an area in the vicinity of the boundarybetween the stomach side region A and the crotch region C and at an areain the vicinity of the boundary between the back side region B and thecrotch region C. Accordingly, no leak of excretions from the nearbyareas of the two boundaries occurs. Moreover, since the leg portionelastic member 161 is disposed in the manner as described above, thediaper 1D is, as shown in FIG. 19, bent serving the part of arrangementof the leg portion elastic member 161 as a bending line and the area inthe vicinity of the bent portion nicely fits to the inguinal part.Accordingly, even if the excretions migrate in the direction of thesecond absorbent core disposed portion 111 from the top of the centralabsorbent core 142, they are prohibited from migration by the nearbyarea of the bent portion. That is, this disposable diaper is moreexcellent in leak-preventive property.

The longitudinal length L13 of the second absorbent core 43 ispreferably from ⅕ to ⅔ the longitudinal length L12 of the diaper. If thelength of the second absorbent core 143 is in this range, the diaper iseasily bent such that a sufficient length of the second absorbent core143 is brought into contact with the wearer's leg area when the diaperis applied to the wearer. Accordingly, a gap is restrained from beingformed between the leg area and the diaper and thus, the leak-preventiveproperty is further enhanced. Although it is most preferable that thefirst and second elastic members 161 a, 161 b constituting the legportion elastic members 161 are continuous in the crotch region C as inthis embodiment, the two elastic members 161 a, 161 b may be slightlyspaced apart from each other inasmuch as that the second absorbent core143 is bent towards the backsheet 3 side and no gap is formed betweenthe second absorbent core disposed portion and the wearer's skin. Inthis case, it is accepted that the end portions of the first and secondelastic members 161 a, 161 b are located in the low rigidity region 4Aand spaced apart from each other. It is also accepted that the firstelastic members 161 a on the left and right sides and the second elasticmembers 161 b on the left and right sides may be continuous with eachother through a communication part traversing the central absorbent core142. It should be noted, however, that in the case where the elasticmembers 161 a, 161 b are spaced apart from each other, the spaced apartdistance between them should be as small as possible taking intoconsideration the rigidity of the absorbent core because there is apossibility that the curved shape is adversely affected by the wearer'swearing state.

In the present invention, since the low rigidity regions 4A are disposedat opposite left and right sides of the absorbent core 4 and the centralportion of each leg portion elastic member 161 passes the low rigidityregion 4A, the absorbent core 40 can easily be bent, and the fitness tothe wearer's leg area of the second absorbent core 143 can is enhanced.Thus, the leak-preventive property is readily exhibited. The method forforming the low rigidity region 4A is not particularly limited inasmuchas the rigidity of a part of the absorbent core can be made lower thanthe rigidity of the rest part. For example, there can be listed a methodfor cutting a part of the absorbent core 40 into a given shape, a methodfor making a part of the absorbent core 40 have a lower basis weightthan the rest part, a method for making a part of the absorbent core 40thinner than the rest part, a method for forming a part of the absorbentcore 40 from a more flexible material than the rest part, a method ofany combination thereof, and the like. As a method for forming the lowrigidity regions 4A, 4A, a method according to this embodiment as laterdescribed or a method for cutting a part of the absorbent core 40 ispreferable.

The low rigidity regions 4A, 4A of the diaper 1D according to thisembodiment are formed by making the basis weight (weight per unit area)of the absorbent core in the region lower than that of the absorbentcore in the adjacent part. The ratio (low rigidity region/inner sideadjacent part) between the basis weight of the low rigidity region 4A,and the basis weight of the absorbent core in a part adjacent to aninner side thereof, and the ratio (low rigidity region/outer sideadjacent part) between the basis weight of the low rigidity region 4Aand the basis weight of the absorbent core in a part adjacent to anouter side thereof are preferably from 0 to 0.5. The difference is basisweight between the low rigidity region 4A and the inner side adjacentpart, and between the low rigidity region 4A and the outer side adjacentpart is preferably at least 100 g/m² or more and particularly preferably200 g/m² or more.

In the diaper 1D according to this embodiment, the second absorbent coredisposed portion elastic member 17 is disposed at the diaper outersurface Q side of the second absorbent core 143 and more specifically,at the diaper outer surface Q side of a part located at an outside areaof the outer edge 44 of the low rigidity region 4A in the secondabsorbent core along the longitudinal direction of the second absorbentcore 143. Moreover, the second absorbent core disposed side elasticmembers 18 are disposed at the opposite side edge portions of theabsorbent core 40 along the opposite side edges 141, 141 of theabsorbent core 40. The two elastic members 17, 18 in this embodiment aredisposed from the stomach side region A over to the back side region B.

By providing the second absorbent core disposed portion elastic members17 and/or the second absorbent core disposed side elastic members 18,fitness with respect to the leg area can be further enhanced, and thus,lead can be prevented more surely. However, in the case where the secondabsorbent core disposed portion elastic members 17 and/or the secondabsorbent core disposed side elastic members 18 are provided, if theelongation stress of those elastic members is large, there is a fearthat the second absorbent cores are irregularly bent at an area otherthan the area where the leg portion elastic member is disposed andfitness to the leg area of the wearer is lowered. From the view point ofpreventing the above-mentioned inconvenience and surely enhancing thefitness to the leg area, the second absorbent core disposed portionelastic member 17 and/or the second absorbent core disposed side elasticmember 18 are preferably lower in elongation stress than the leg portionelastic member 161.

In the case where the second absorbent core disposed portion elasticmember 17 and the second absorbent core disposed side elastic member 18are disposed at opposite sides of the diaper, or in the case where twoor more of the elastic members 18 are disposed at opposite sides of thediaper, the total elongation stress of the elastic members 17, 18disposed at one side of the diaper is preferably lower than theelongation stress of the leg portion elastic member 161 disposed at thesame side. The elongation stress of the second absorbent core disposedportion elastic member 17, the second absorbent core disposed sideelastic member 18 and the leg portion elastic member 161 can be measuredas follows. Test pieces are cut out each having a longitudinal length of100 mm in a shrunk state with respect to the second absorbent coredisposed portion 111 and the low rigidity region A in the crotch regionC of the diaper 1D and they are subjected to a tensile test using atensile test machine (manufactured by Orientic Corp., 50 mm in chuckdistance and 300 mm/min in test speed) and the stress at 25% stretchingis measured. The results are converted in terms of the test piece widthto obtain the respective elongation stresses.

The opposite side edges 141 of the absorbent core 40 in the diaper 1Daccording to this embodiment are covered with a water-repellent sidesheet 19. Each side sheet is formed in the shape of belt. One side edgeportion of each side sheet is joined to the topsheet 2 at the skincontact surface P side of the absorbent core 40, and the other side edgeportion is joined to the backsheet 3 at the non-contact surface (samesurface as the outer surface Q) side. Liquid ooze from the secondabsorbent core 143 can be prevented by covering with the side sheet 19.The other side edge portion of the side sheet 19, as shown in FIG. 20,may be joined to an extended part of the backsheet 3 which is extendedfrom a side edge 141 of the absorbent core 40.

This disposable diaper 1D includes one pair of three-dimensional gathers112, 112 which are formed from the stomach side region A over to theback side region B. Each three-dimensional gather 112 has a free end 113at a widthwise inner side of the absorbent main body 10 and a fixed end(basal end) at an outer side. An elastic member 116 for forming thethree-dimensional gather is fixedly arranged, in its stretched state, atthe free end 113 of each three-dimensional gather 111 along the free end113. Each three-dimensional gather 112 is provided by fixing thewater-repellent gather forming sheet 115 having the elastic member 116to the topsheet 2. The gather forming sheet 115 and the side sheet 19are spaced apart from each other. Between those sheets 115 and 19, aside absorbent region 117 having a non-water-repellent surface isformed. Since the disposable diaper according to this embodiment has theabove-mentioned construction, even if urine, etc. leak out beyond thearrangement part of the leg portion elastic member 161, they can beabsorbed through the side absorbent region 117. Thus, the occurrence ofleak can more surely be prevented.

In the disposable diaper 1D according to this embodiment, the first andsecond elastic members 161 a, 161 b forming one of the pair of left andright leg portion elastic members 161 and the first and second elasticmembers 161 a, 161 b forming the other are divided. Those elasticmembers are not present at least at the widthwise central part of thecrotch region C. That is, the first and second elastic members 161 a,161 b include a portion extending towards the central portion in awidthwise direction of the diaper from the portion for forming the legportion elastic member 161. An end portion of the extended portion islocated slightly inside of the side edge portion of the centralabsorbent core 142.

A plurality of body peripheral portion elastic members 118 are arrangedat prescribed intervals on a body peripheral portion DS of the stomachside region A and back side region B. The body peripheral portion DSrefers to a portion which is located bellow the position where the waistportion elastic member 151 is disposed but above the leg openingportions 16, 16 in a state that the waist opening portion 15 facesupward, as shown in FIG. 16. The body peripheral elastic members 118 arefixedly arranged at least at an outside area of the opposite side edges141, 141 of the absorbent core such that elastic stretchability can beexhibited. At least at a widthwise central portion M of the portionwhere the absorbent core 40 exists, the body peripheral elastic members118 are not arranged or no elastic stretchability is exhibited. Theexpression “no elastic stretchability is exhibited” refers to a state inwhich although the elastic member is arranged, elastic stretchability islost at that portion by thermal treatment such as heat sealing or thelike, or the stretched state is released so as not to exhibit elasticstretchability.

In the diaper 1D according to this embodiment, the elastic members 151,161 and 181 are all fixed through an adhesive agent between the twosheet materials 21, 22 constituting the outer layer body 20, i.e.,between the inner layer sheet 121 and the outer layer sheet 122 formingthe outer surface.

The material for forming the component members of the disposable diaper1D according to this embodiment will now be described. As the materialfor forming the topsheet 2, the backsheet 3, the absorbent core 40, theinner layer sheet 121, the outer layer sheet 122 and the like, thosewhich has heretofore been used for disposable diapers or the like can beused without any particular limitation.

As the elastic members of the various portions, various kinds of elasticmembers which have heretofore been used for shorts type disposablediapers or the like can be used. As examples of the raw material forforming the elastic member, there can be listed, for example, syntheticrubber such as styrene-butadiene, butadiene, isoprene, neoprene and thelike, natural rubber, EVA, expansible polyolefin, spandex, foamurethane, and the like. As examples of a form of the elastic member ofthe various portions, there can be used various kinds of forms. The formof the elastic members 151, 161 (161 a, 161 b) is preferably a belt-likeone having a predetermined width (flat rubber, and the like). The formof the elastic member 118 is preferably a thread-like one (thread rubberand the like), while the form of the elastic members 17, 18, 116, athread-like one (thread rubber or the like), a thread-like one having apredetermined width (flat rubber or the like) and a film-like one(urethane film or the like) are preferable.

As the material of the side sheet 19 and the three-dimensional gatherforming sheet 115, various kinds of water-repellent sheet materialswhich have heretofore been used for shorts-type disposable diapers orthe like can be used. For example, span bond nonwoven fabric, and spanbond-melt blown-span bond nonwoven fabric are preferable.

The third invention is not limited to the above-mentioned embodimentsand it can be changed and modified in accordance with necessity andwithout departing from the gist of the present invention. For example,the present invention can be applied not only to the shorts-typedisposable diaper but also to a so-called flat-type disposable diaper inwhich a fastening tape is disposed at each opposite side edge portion ofthe back side region. The present invention can be applied to adisposable diaper in which the topsheet and the backsheet form the outerconfiguration of the diaper and which does not include an outer layerbody. Instead of an arrangement in which a low rigidity region isprovided, as in this embodiment, so that the diaper is easily bent atthe position where the leg portion elastic member is disposed, it may bedesigned such that the second absorbent core is readily bent by reducingthe rigidity of the whole absorbent core or by preliminarily providing afolding line. It suffices that the low rigidity region is spaced apartat least at a part thereof from the side edge of the absorbent core. Forexample, it is also accepted that the low rigidity region is curved inan arc-like shape such that the low rigidity region is spaced apart atits central portion from the side edge of the absorbent core but itreaches the side edge at its opposite end portions. The outerconfiguration of the absorbent core is not limited to a square shape butit may be formed in a trapezoidal shape and a hourglass shape. Theconfiguration of the low rigidity region may be formed in a spindleshape, a square shape and the like. The leg portion elastic member isnot limited to those which is composed of the first and second elasticmembers but it may be those which is composed of a single piece ofelastic member.

In the disposable diaper of the third invention, the leg flap portionhaving a fluid absorptive/retentive performance can be closely fit tothe wearer's skin. This diaper is excellent in fitness to the wearer'singuinal portion and capable of surely preventing leak around the legarea.

EXAMPLES

The present invention will now be illustrated in greater detail withreference to Examples. The following Examples are presented as beingexemplary of the present invention and should not be considered aslimiting.

Example 1

A disposable diaper (example 1) of the form as shown in FIGS. 8 and 9which have the dimensions and ratios as shown in Table 1.

Comparative Examples 1 to 3

A disposable diaper (comparative example 1) was prepared in the samemanner as in the embodiment 1 only except that L7 in the example 1 waschanged to from 57 to 100. A disposable diaper (comparative example 2)was prepared in the same manner as in the example 1 only except that L6in the example 1 was changed to from 65 to 40. A disposable diaper(comparative example 3) was prepared in the same manner as in theexample 1 only except that L7 in the example 1 was changed to from 57 to100 and that L6 was changed from 65 to 40.

Evaluation

With respect to the disposable diapers of examples and comparativeexamples, use test was conducted by 10 adult monitors for each. Based onthe under-listed evaluation standard, the respective diapers wereevaluated as to (a) whether or not a trunks-like shape is formed, (b)easiness to put on each diaper, (c) leak-preventive property, and (d)fitness. The results of evaluation are additionally shown in Table 1.

Whether or not a Trunks-Like Shape is Formed:

-   -   A: a trunks-like shape is formed    -   B: not clear (a trunks-like shape can be formed, if tried very        hard at the time of putting on the diaper)    -   C: definitely not a trunks-like shape        Easiness to Put on Each Diaper    -   A: easy (8 monitors or more answered as easy)    -   B: not clear (5 to 7 monitors answered as easy)    -   C: not easy (4 monitors or less answered as easy)        Leak-Preventive Property: Each diaper was applied to the human        body model and have him/her laid on his/her side, and a        physiological solution of sodium chloride of 150 g/times was        caused to be excreted from the crotch region. Evaluation was        made by checking the number of times until the solution leaks        through the crotch region.    -   S: 4 times or more    -   A: 3 times    -   B: 2 times    -   C: Once        Fitness: Obtained answers as for whether or not the sense of        fitness to the leg area is satisfactory and evaluation was made        counting the number of monitors who answered as satisfactory.    -   S: 9 or more monitors    -   A: 7 to 8 monitors    -   B: 5 to 6 monitors

C: 4 or less monitors TABLE 1 Example Comparative Examples 1 1 2 3Smallest width L4 of crotch region 420 430 430 430 Largest width L5 ofdiaper 640 640 640 640 Shortest distance L6 between innermost 65 65 4040 side edge of leg portion elastic member and outer side edge of flapportion Distance L7 between outermost side 57 100 57 100 point andinnermost side point of outer side edge of leg flap portion.Longitudinal length L8 of crotch region 420 420 420 420 Region whereoutermost side point of back side back side back side back side outerside edge of leg flap portion exists Presence of second absorbent coreyes yes yes yes Ratio Ratio (L4/L5) 0.66 0.67 0.67 0.67 Ratio (L6/L4)0.13 0.15 0.09 0.09 Ratio (L7/L8) 0.14 0.24 0.13 0.23 Evalu- Whether ornot a trunks- A B C C ation like shape is formed Easiness to pat ondiaper A C B C Leak prevention (particularly S B B B at lying on one'sside) Fitness (particularly around S B C C legs)

From the results shown in Table 1, it is known that the diapers of theexamples take the shape of trunks during wearing the diaper, areexcellent in leak-preventive property and designability, and are veryeasy to put on or apply. In contrast, the diapers of the comparativeexample do not take the shape of trunks because the ratios of some ofthem are not in the range of present invention or they are difficult toput on or apply even though they take the shape of trunks.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not be regarded as adeparture from the spirit and scope of the invention, and all suchmodification as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

1. A disposable diaper comprising a fluid-permeable topsheet, afluid-impermeable backsheet and a fluid-retentive absorbent coreinterposed between said topsheet and said backsheet, said disposablediaper having a stomach side, a back side and a crotch region positionedbetween said stomach side and said back side, leg portion elasticmembers being disposed in their stretched states at a pair of legportions disposed around the wearer's leg areas, wherein lengthwiseopposite end portions of said leg portion elastic members are located atwidthwise outside areas of side edges of said absorbent core,respectively and central portions of said leg portion elastic membersare curved in such a manner as to pass a widthwise inner direction ofthe side edges of said absorbent core at a crotch region of the diaper,said absorbent core at said crotch region of said diaper being dividedinto a pair of lateral absorbent cores located at widthwise outsideareas of said leg portion elastic members, respectively, and a centralabsorbent core located between said pair of lateral absorbent cores bysaid pair of leg portion elastic members, said lateral absorbent coresare when in wear, being bent towards said backsheet and elastic membersdisposed below said lateral absorbent cores along the longitudinaldirection of said diaper.
 2. The disposable diaper according to claim 1,wherein a longitudinal length of said lateral absorbent cores is ⅕ to ⅔of a longitudinal direction of said diaper.
 3. The disposable diaperaccording to claim 1, wherein the elastic members are disposed at thediaper outer surface side or said lateral absorbent cores along alongitudinal direction of said lateral absorbent cores, and said elasticmembers are lower in elongation stress than said leg portion elasticmembers.
 4. The disposable diaper according to claim 1, wherein leg flapside elastic members are disposed at the opposite side edge portions ofsaid absorbent core at the crotch region of said diaper along theopposite side edges of said absorbent core, and said leg flap sideelastic members are lower in elongation stress than said leg portionelastic members.
 5. The disposable diaper according to claim 1, whereinsaid absorbent core at the crotch region of said diaper includes a pairof lower rigidity regions, lower than the remaining regions, said pairof lower rigidity regions being located away from the opposite sideedges of said absorbent core, and said leg portion elastic members aredisposed such that their central portions pass said lower rigidityregions, respectively.
 6. The disposable diaper according to claim 1,wherein the opposite side edges of said absorbent core are covered withwater-repellent side sheets, respectively, a pair of three-dimensionalgathers are formed from a stomach side region to a back side region,each of said three-dimensional gathers being fixedly provided with awater-repellent gather forming sheet having an elastic member, saidgather forming sheet and said side sheet being located away from eachother, and a side absorption area having a non-water-repellent surfaceis formed between said gather forming sheet and said side sheet.